Spring recommendation for GN1s

[RmvBfrFlght]

Meant to add that with the amount of SA being pulled that the engine will get erratic. So if false knock that can easily cause issues with how the engine runs.

If the knock is real will need to reduce the SA as the RPM increases.When looking at the plugs go outside in the sunlight and use an eye-lope or magnifier of some sort.

RemoveBeforeFlight

 

[jpwalt1987]

Checked the plugs. No signs of detonation but definatly need to lean it out some. Too rich. Going to dual back the AFR from 10.2 to 10.6 and retest.

 

[EVIL]

What ever happened?

D

 

[jpwalt1987]

I installed a set of PAC 1201 springs along with their retainers and locks. Engine pulled hard all the way to 6500. I wound up breaking a rocker pedestal and a rocker shaft. The helicoil insert wasn't deep enough. Got that fixed along with a new Borg-Warner turbo from WORK Turbochargers. All back together now and running like a bat out of hell. Need to add a second DW pump as one just isn't cutting it. I've seen 29 psi of boost on the powerlogger for a quick pull with zero detonation. 11.0:1 afr with Alky on 7. 18* timing.

PAC 1201 springs
Comp 885 lifters
Smith Brothers .112 wall 5/16 pushrods
Borgwarner S300sx3 66/68 turbo

 

[TurboTdr3.8]

I installed a set of PAC 1201 springs along with their retainers and locks

Whats heads and cam are you running with this combo ? What seat and nose pressure did you finally come up with also ?

 

[jpwalt1987]

.

 

[jpwalt1987]

Double post

 

[jpwalt1987]

The heads are ported GN-1 heads. T&D roller rockers 1.65 on the intakes and 1.55 on the exhaust. The cam is a DLS 218/218 billet roller .540/.512 lift. As for the pressures, I would have to look back at my notes to see what they ended at. I'll see what I can find.
^^^ our combos are pretty similar aside from turbo and intercooler.

 

[TurboTdr3.8]

our combos are pretty similar aside from turbo and intercooler

That was what I was wondering about , because I went to those springs 1201 but my previous cam was too big for them . I ran into spring bind big time witch I had 1.60 t&d rockers with a .530 /.545 cam

 

[jpwalt1987]

Sorry it took so long. Here are my measurements.

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[TurboTdr3.8]

Thanks similar results with mine .